Devices and methods for vertebral bone realignment

ABSTRACT

Methods and apparatus for providing correction of one or more maladies or conditions of the spinal column of a living being. In one embodiment, the apparatus includes an implantable device configured to be selectively adjustable in one or more portions thereof so as to permit correction of asymmetries or irregularities of the spinal column via insertion into one or more affected intervertebral disc spaces. In one variant, the implantable device includes upper and lower host elements which are hinged or can pivot relative to one another, and an insertable distraction mechanism which is adjustable to enable one side or the other of the implantable device to alter height. In another variant, both sides of the implantable device can be adjusted for height via the host elements and one or more pivots or hinges. In one implementation, the distraction mechanism is adjustable from multiple approaches into the disc space.

PRIORITY

This application is a continuation of and claims priority to co-ownedand co-pending U.S. patent application Ser. No. 15/793,895 filed on Oct.25, 2017 entitled “DEVICES AND METHODS FOR VERTEBRAL BONE REALIGNMENT,”which claims priority to U.S. Provisional Patent Application Ser. No.62/496,721 entitled “DEVICES AND METHODS FOR VERTEBRAL BONEREALIGNMENT,” filed Oct. 25, 2016, each of which is incorporated hereinby reference in its entirety.

COPYRIGHT

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent files or records, but otherwise reserves all copyrightrights whatsoever.

BACKGROUND 1. Field of the Disclosure

This disclosure relates generally to medical devices, and in oneexemplary aspect to bone fixation systems, components thereof, andmethods of implant placement, which can be used to, inter alia, adjust,align and maintain the spatial relationship(s) of adjacent bones or bonyfragments during and/or after surgical reconstruction of skeletalsegments.

2. Description of Related Technology

Whether from congenital malformation, degenerative disease, traumaticdisruption, infection or neoplastic invasion, alteration in theanatomical alignment between the spinal vertebrae can cause significantpain, deformity, neurological decline and disability. Spinal disease isa major health problem in the industrialized world and the surgicaltreatment of spinal pathology is an evolving discipline. The traditionalsurgical treatment of abnormal vertebral motion and/or formation is thecomplete immobilization and bony fusion of the involved spinal segmentand an extensive array of surgical techniques and implantable deviceshave been formulated to accomplish the treatment objective.

Regardless of the specific objectives of surgery, many surgeons employimplantable devices that maintain the desired spatial relationship(s)between adjacent vertebral bodies. However, conventional implantabledevices are limited in that they are, inter alia, primarily “one sizefits all,” including standardized configurations and sizes which arenon-adjustable and/or not particularly adapted for certain applications.Thus, such conventional implants may be insufficient for treatment ofpatients with unusual or complex spinal curvatures and maladies, whichmay occur in conditions such as e.g., coronal plane deformity (such asscoliosis), sagittal plane deformity (such as alternation in segmentalkyphosis or lordosis), axial translation, spondylolisthesis, etc.

Hence there is a salient need for alternative methods and devices forthe alteration and/or correction of spinal curvature, which, inter alia,enable variable and/or adjustable configurations for implantabledevices, such as to realign adjacent vertebrae according to the spinalstructure or curvature of a specific subject.

SUMMARY

Improved devices, systems, and methods to alter vertebral alignment aredescribed herein.

In one aspect, an implantable device is disclosed. In one embodiment,the device comprises a distraction mechanism, and a first member or ahost member configured to at least partly retain the distractionmechanism.

In one variant, the host member comprises a set of substantially planarelements configured to articulate relative to one another around atleast one axis, so as to permit insertion and/or removal of thedistraction mechanism. The distraction mechanism can cause theimplantable device to change a height of one side so as to allow forintervertebral correction of e.g., scoliosis.

In another variant, the host member is configured to enable adjustmentof height of both sides of the implant.

In another aspect, a method of inserting an implantable device within anintervertebral space is disclosed. In one embodiment, the methodincludes inserting an assembled implant device in the disc space, andadjusting a height of at least a portion thereof so as to compensate forasymmetries in the disc space caused by, e.g., scoliosis.

In another aspect, a method of treating a spinal misalignment isdisclosed. In one embodiment, the method includes utilizing an implantassembly to alter the spinal alignment of a target functional spinalunit in the coronal plane in order to treat coronal plane deformitiessuch as, e.g., scoliosis.

In another embodiment, the method includes utilizing an implant assemblyto alter the spinal alignment of a target functional spinal unit in thesagittal plane in order to treat sagittal plane deformities such as,e.g., abnormal lordosis and/or kyphosis.

In yet another embodiment, the method comprises utilizing an implantassembly to alter the spinal alignment of the target functional spinalunit in the axial plane in order to, for example, treat translationaldeformities such as e.g., anterior/posterior or lateralspondylolisthesis.

In another aspect, a distraction mechanism for use within an implantabledevice is disclosed. In one embodiment, the distraction mechanismincludes a piston which utilizes a working fluid to drive the piston(and hence a top portion of the mechanism) into compressive contact withan inferior surface of a superior vertebral segment. In anotherembodiment, the mechanism uses a mechanical (non-fluidic) arrangementfor the compression (e.g., worm drive, gear mechanism, etc.).

In a further aspect, a system for correction of spinal conditions isdisclosed. In one embodiment, the system includes: (i) a host housingmember, (ii) a distraction mechanism, and (iii) a tool for adjusting thedistracting mechanism after implantation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C show diagrammatic representations of a spinal vertebral bonein lateral, top, and posterior views, respectively.

FIGS. 2A and 2B illustrate diagrammatic representations of a functionalspinal unit (FSU), which includes two adjacent vertebrae and theintervertebral disc disposed between them, in a posterior view and aposterior perspective view, respectively.

FIG. 3 shows a diagrammatic representation of the posterior aspect of apatient who is positioned in a lateral decubitus orientation.

FIG. 4 illustrates a cross sectional view of a first exemplary targeteddisc space in the lumbar spine.

FIG. 5 illustrates a cross sectional view of a second exemplary targeteddisc space in the lumbar spine, illustrating various approaches thereto.

FIGS. 6A and 6B illustrate top perspective views of one embodiment of animplantable device according to the present disclosure.

FIGS. 7A and 7B respectively show a top plan view and a side plan viewof the device of FIGS. 6A and 6B, in a closed position, with anexemplary distraction mechanism installed therein.

FIG. 7C shows a side plan view of the device of FIGS. 6A and 6B, in anopen position, with the exemplary distraction mechanism installedtherein.

FIGS. 8A-8C respectively show a top perspective view, a side elevationview, and a front elevation view of the device of FIGS. 6A and 6B.

FIGS. 9A-9D respectively show a top perspective view, a top elevationview, a side elevation view, and a front elevation view of oneembodiment of the exemplary distraction mechanism of FIGS. 6A and 6B.

FIGS. 10A and 10B respectively show a top perspective view and a frontelevation view of a first exemplary component of the exemplarydistraction mechanism of FIG. 9.

FIGS. 10C and 10D respectively show a top perspective view and a bottomperspective view of a second exemplary component of the exemplarydistraction mechanism of FIG. 9.

FIGS. 11A and 11B respectively show a top perspective view and a sidecross-sectional view (taken along line A-A) of the exemplary distractionmechanism of FIG. 9.

FIGS. 11C and 11D respectively show a side plan view of the device ofFIGS. 6A and 6B, and a front cross-sectional view (taken along line B-B)of the exemplary distraction mechanism of FIG. 9.

FIG. 12A shows a front elevation view of a lumbar spine with a coronalplane deformity (such as, for example, scoliosis).

FIG. 12B shows a front elevation view of the lumbar spine of FIG. 12Awith the device installed to produce a deformity (scoliosis) correction.

FIGS. 13A and 13B respectively show a top elevation view and a side planview of another embodiment of the implantable device with the exemplarydistraction mechanism positioned in an anterior aspect of the device.

All Figures © Copyright 2013-2017. Samy Abdou. All rights reserved.

DETAILED DESCRIPTION

In order to promote an understanding of the principals of thedisclosure, reference is made to the drawings and the embodimentsillustrated therein, and wherein like numerals refer to like partsthroughout. Nevertheless, it will be understood that the drawings areillustrative and no limitation of the scope of the claims is therebyintended. Any such alterations and further modifications in theillustrated embodiments, and any such further applications of theprinciples of the disclosed devices as illustrated herein arecontemplated as would normally occur to one of ordinary skill in theart.

Overview

In one aspect, improved devices, systems, and methods to alter vertebralalignment are described herein. Specifically, a variable heightimplantable device and its systems (e.g., related components) andmethods of use are disclosed herein.

It will be appreciated that in a variety of disorders, the vertebralbones of a human (or other vertebrate organism) may become mal-alignedand produce, among other conditions, translational, rotational and/orangulational deformities of the spinal column. The devices and methodsdisclosed herein can advantageously be used in the treatment of manyspinal disorders, such as, inter alia, coronal plane deformity (such asscoliosis), sagittal plane deformity (such as alternation in segmentalkyphosis or lordosis), axial translation, vertical translation,spondylolisthesis, and the like.

In one implementation, a spinal segment to be surgically treated usingthe methods and apparatus disclosed herein includes at least a superiorvertebral bone, an immediately inferior vertebral bone, and theintervening intervertebral disc space. A spinal segment comprised of twoimmediately adjacent vertebral bones and the intervertebral disc spacedisposed therebetween defines a “functional spinal unit” (FSU)—asdescribed further below. An FSU to be surgically treated will bereferred to as a target FSU and its intervertebral disc space as atarget intervertebral disc space.

In one embodiment, a method of treatment includes entering the targetintervertebral disc space and removing at least a portion of theviscoelastic material that comprises the natural nucleus pulposus within(at least a portion of) the intervertebral disc space. The targetintervertebral disc space may be accessed using various surgicalapproaches (such as e.g., a direct anterior approach, an anterolateralapproach, and/or a direct lateral approach, posterolateral approach,posterior approach, etc.), thereby creating one or more operativecorridors at desired vertebral level(s) of the spinal column.

After removal of the viscoelastic material, the method further includesimplanting a variable-height orthopedic implant into the targetintervertebral disc space. The implanted orthopedic device is thenactuated to vary a height of the implant in at least one aspect, and atleast a portion of the implant is left in place in a substantially fixedposition after the surgical procedure is complete.

The implanted apparatus enables, inter alia, customized (andheterogeneous) adjustment in distraction as between different targetintervertebral disc spaces (and even different portions of the sametarget intervertebral space(s)). This is accomplished in one embodimentvia use of one or more variable-geometry distraction mechanism used inconjunction with an implantable member, the latter which at least partlyreceives the former so as to create an implantable assembly that can beadjusted by the surgeon to achieve the desired geometry and spatialrelationships.

Detailed Description of the Exemplary Embodiments

Exemplary embodiments of the apparatus and methods of the presentdisclosure are now described in detail.

It will be appreciated that while the exemplary embodiments aredescribed with respect to human beings, various of the methods,apparatus and systems disclosed herein may be applied to other specieshaving a spinal structure (i.e., vertebrates).

FIGS. 1A-1C show diagrammatic representations of a spinal vertebral bone802 in multiple views. For clarity of illustration, the vertebral boneof FIGS. 1A-1C and those of other illustrations disclosed herein arerepresented schematically and it should be appreciated that actualvertebral bodies may include anatomical details that are not shown inthese figures. Further, it is understood that the vertebral bones at agiven level of the spinal column of a human or animal subject willcontain anatomical features that may not be present at other levels ofthe same spinal column. The illustrated vertebral bones are intended togenerically represent vertebral bones at any spinal level withoutlimitation. It will be appreciated that the disclosed devices andmethods may be employed at any applicable spinal level.

Additionally, the term “sagittal plane”, as used herein, refers withoutlimitation to the plane that splits the body into left and rightsegments. The terms “mid-sagittal plane” or “median plane”, as usedherein, refer to the plane that specifically splits the body into equalleft and right halves. The term “coronal plane”, as used herein, referswithout limitation to the plane that divides the body into anterior(front) and posterior (back) segments. It will be appreciated that thecoronal and sagittal planes are substantially perpendicular to oneanother.

As can be seen in FIGS. 1A-1C, the vertebral bone 802 contains ananteriorly-disposed vertebral body 804, a centrally-disposed spinalcanal 806 and a posteriorly-placed lamina 808. The pedicle segments 810of the vertebral bone 802 form the lateral aspects of the spinal canal806 and connect the laminas 808 to the vertebral body 804. The spinalcanal 806 contains neural structures such as the spinal cord and/ornerves. A midline protrusion termed the spinous process (SP) extendsposteriorly from the medial aspect of laminas 808. A protrusion extendslaterally from each side of the posterior aspect of the vertebral bone802 and is termed the transverse process (TP). A right transverseprocess (RTP) extends to the right from the lateral aspect of the rightpedicle. A left transverse process (LTP) extends to the left from thelateral aspect of the left pedicle. A superior protrusion extends abovethe lamina 808 on each side of the vertebral midline, and is termed thesuperior articulating process (SAP). An inferior protrusion extendsinferiorly below the lamina 808 on each side of the vertebral midline,and is termed the inferior articulating process (IAP).

As a brief aside, it is noted that the posterior aspect of the pedicle810 can be accessed at an indentation 811 in the vertebral bone 802between the lateral aspect of the SAP and the medial aspect of the TP.In surgery, it can be common practice to anchor a bone fastener into thepedicle portion 810 of a vertebral bone 802 by inserting the fastenerthrough indentation 811 and into the underlying pedicle 810 in aposterior to anterior direction.

FIGS. 2A and 2B illustrate a functional spinal unit (FSU), whichincludes two adjacent vertebrae and the intervertebral disc disposedtherebetween. The intervertebral disc resides between the inferiorsurface of the upper vertebral body and the superior surface of thelower vertebral body, although it is not specifically shown in thefigures. FIG. 2A shows the posterior surface of the adjacent vertebraeand the articulations between them. FIG. 2B shows an oblique view. TheFSU contains three joints between the two vertebral bones, with theintervertebral disc comprising the anterior joint. The posterior jointsinclude a facet joint 814 on each side of the midline, wherein eachfacet joint 814 is comprised of the articulation between the IAP of thesuperior vertebral bone and the SAP of the inferior bone.

These illustrations and definitions of anatomical structures are knownto those of ordinary skill in the art. They are described in more detailin Atlas of Human Anatomy, by Frank Netter, third edition, Icon LearningSystems, Teterboro, New Jersey, the entirety of which is incorporatedherein by reference. It should be appreciated that the directionallanguage and terms regarding orientation such as upper, lower, upward,downward etc., are used throughout merely for convenience of descriptionand are not limiting.

A method of device implantation is now illustrated and described. One ormore FSUs is/are targeted for surgical manipulation and treatment. Inpreparation for surgery, the patient can be, but is not necessarily,placed in a lateral decubitus position, such as that shown in FIG. 3. Itis understood that a target intervertebral disc space may be accessedusing any known surgical approach, and the illustrated method serves asa non-limiting example.

The level(s) of the spine that is to be implanted can be localized on animaging modality (such as X-ray, CT, MRI and the like) in at least oneplane. After the customary sterile preparation of the operative site,the surgeon can localize an incision point on the skin that is anteriorto coronal plane T. Preferably, but not necessarily, the incision may bemade immediately anterior to a coronal plane that is parallel to coronalplane T and passes through the anterior-most (tip) aspect of the targetdisc space. A lateral corridor “V” (FIG. 4) can be made through the skin118 from the flank incision and taken onto the target intervertebraldisc space. In the illustrated embodiments, the disc space may beentered using one or more of three locations shown in FIG. 5; i.e.: a)medial to the aorta and may comprise the midline (and/or its branches,the common iliac arteries, etc.) to form a direct anterior approach(505); b) lateral to the aorta but anterior to the Psoas Major muscle—toform an anterolateral approach (507); and c) laterally and through thebody of the Psoas Major muscle—to form a direct lateral approach (509).The insertion corridor of a direct lateral approach is known to thoseskilled in the art as the “XLIF” procedure, among other names. See“Extreme Lateral Interbody Fusion (XLIF): a novel surgical technique foranterior lumbar interbody fusion”-Ozgur, Aryan et al. in Spine J. 2006July-August; 6(4):435-43, which is incorporated herein by reference inits entirety.

In one implementation of the method, the target intervertebral discspace is entered using the anterolateral approach 507, shown in FIG. 5,which is at least partially positioned between the lateral Aorta and theanterior surface of the ipsilateral Psoas major muscle. After removal ofat least a portion of the nucleus pulposus of the target intervertebraldisc space, a variable-height implant 104 (see FIG. 6A) may be placedinto the disc space. Preferably, the implant 104 extends across themidsagittal plane of the disc space with one end segment positioned ontothe left side of the apophyseal ring of the inferior vertebral bone anda second end segment positioned on the right side of said apophysealring (as subsequently shown and discussed with respect to FIGS. 12A and12B), although it will be appreciated that other orientations anddispositions may be used (as subsequently shown and discussed withrespect to FIGS. 13A and 13B). Additionally, the present disclosurecontemplates that the implants 104 may be configured with a more roundor oval form factor, and rotated at varying degrees (e.g., around anaxis generally co-linear or parallel with the spinal column of thepatient) so as to best accommodate the particular configuration of theprevailing target intervertebral disc space. Moreover, such rotations orother positional variations may be applied on a per-implant basis; e.g.,wherein one target space uses one rotation/orientation, and anothertarget space within the same patient uses another.

In one variant of the method, the superior and inferior vertebral bonesof the target FSU are distracted away from one another in order toincrease the vertical height of the target intervertebral disc spaceduring implantation. Such optional distraction step may be performedwith, for example, one or more distraction instrument(s) or devices thatare used during surgery, and which are removed prior to the end of theprocedure or after placement of the orthopedic implant(s); however, itis also recognized that dissolvable, inflatable, or other means ofdistracting may be utilized, other than the one or more removabledistraction devices previously referenced.

In another embodiment, the method includes inserting a variable-heightimplantable device into a target intervertebral disc space in order tochange the coronal plane alignment of the target FSU. The implant may beplaced into the target intervertebral disc space using any of the knownsurgical approaches, such as, for example, the direct anterior approach,the anterolateral approach, and/or the direct lateral approach,discussed supra.

In one variant of the method, the implant is inserted with the firstlateral side of the implant (i.e., a side of the implant that will bepositioned closest to a first lateral side surface of the targetintervertebral disc space) having a height that is less than or equal tothe height of the second lateral side (i.e., a side of the implant sidethat will be positioned closest to the second lateral side surface,opposing the first lateral side surface, of the target intervertebraldisc space) (see FIGS. 12A and 12B). After the implant is positioned ata desired position within the target intervertebral disc space, amechanism of the implant is actuated so as to increase the height ofone, but not both, of the first lateral side or the second lateral sideof the implant. Thus in one implementation, a coronal section though theimplanted intervertebral disc space will show that the implant, afteractuation of the distraction mechanism, is wedge-shaped with thedistance between the inferior surface of the superior vertebral bone andthe superior surface of the inferior vertebral bone being greater on onelateral side surface of the target intervertebral disc space than on theopposing lateral side surface of said disc space.

In another variant, the implant comprises an anterior side (i.e., a sideof the implant that will be positioned closest to the anterior midline(mid-sagittal) of the implanted intervertebral disc space) and anopposing posterior side (i.e., a side of the implant that will bepositioned closest to the posterior midline (mid-sagittal) of theimplanted intervertebral disc space) (see FIGS. 13A and 13B). Theimplant is positioned at the desired position within the intervertebraldisc space, and then the mechanism within the implant is actuated so asto increase the height of one, but not both, of the anterior side or theposterior side of the implant. Thus in one implementation, a mid-sagittal section though the implanted intervertebral disc space willshow that the implant, after actuation of the distraction mechanism, iswedge-shaped with the distance between the inferior surface of thesuperior vertebral bone and the superior surface of the inferiorvertebral bone being greater at one of the anterior or posterior sidesides of the implanted intervertebral disc space than at the opposingside of the target disc space.

FIGS. 6A and 6B illustrate an embodiment of the variable-height implanthaving a distraction mechanism according to the present disclosure. Theillustrated implant 104 may, for example, comprise a first member 105(i.e., a host member) having an “upper” element 1051 a with superiorsurface adapted to abut the inferior surface of the vertebral boneimmediately superior to the target disc space, and a “lower” element1051 b with an inferior surface adapted to abut the superior surface ofthe vertebral bone immediately inferior to the target disc space. Thesuperior and inferior surfaces are connected by at least one sidesurface. In the present embodiment, a hinge 1052 or other mechanism forarticulation is positioned at one side of upper and lower elements 1051a, 1051 b and is configured to allow the inferior surface to moverelative to the superior surface, thereby increasing a distancetherebetween. The hinge may be a malleable or even frangible member thatis connected each of the superior and inferior surfaces. Alternativelyor additionally, the hinge may comprise two abutment or engagementsurfaces, each disposed on one of the superior and inferior surfaces ofthe first member, which rotate about a common axis (such as, forexample, about a central pin). Cavities 1054 open within and/or onto thesuperior and inferior abutment surfaces and are adapted to accept and/orhouse a bone forming material (including, e.g., allograft and autograftbone) in order to form a bony fusion across member 105 and between thesuperior and inferior vertebral bones.

As can be seen in FIGS. 6A and 6B, the variable-height implant 104further comprises a distraction mechanism 205 (i.e., a second expandablemember), which is configured to be at least partially positioned withinand/or at least partially seated within the first member 105. FIG. 6Aillustrates a position for the insertion of the distraction mechanism205 into the first member 105. After the distraction mechanism 205 isseated within the first member 105 (as in FIG. 6B), a surface 20544extends through a window 1053 of the first member 105. A surface 20542of mechanism 205 abuts the undersurface of upper element 1051 a of thefirst member 105. Thus, when the distraction mechanism is seated, thesurface 20542 abuts the first member 105, whereas the surface 20544abuts the vertebral bone. This is further illustrated in the sectionalview of FIG. 11B.

In one embodiment, upon actuation, the distraction mechanism 205increases a height of at least one side of the first member 105. Forexample, upon actuation of the distraction mechanism 205, a distancebetween the upper and lower elements 1051 a, 1051 b is increased on atan expandable side 1058 (i.e., an end opposing the hinge 1052) of thefirst member 105. In alternate examples, the distraction mechanism mayincrease the height of more than one side of the first member 105.However, as illustrated herein (see FIGS. 7B and 11B), the increase inheight is at least greater on one side (i.e., the expandable side 1058)than the other side(s)—so that the implant assumes a “wedge-like”configuration that can be used to realign spinal bones.

An exemplary contracted position 1040 of the implant 104 is shown inFIGS. 7A and 7B, while an exemplary expanded position 1042 is shown inFIG. 7C. It will be appreciated that the implant 104 can be adjusted toassume various intermediate positions and/or positions having a greaterdistance between the upper and lower elements 1051 a, 1051 b. It isnoted that, during implantation, the first member 105 is preferablyinserted into the disc space in a configuration where the opposing sidesare of substantially equal height (position 1040 of FIGS. 7A and 7B).After implantation of the implant 104, subsequent actuation of thedistraction mechanism 205 will cause the first member 105 to assume awedge-shaped configuration (position 1042 of FIG. 7C).

In one implementation, the distraction mechanism 205 is adapted to bedelivered to the surgeon as a separate device, and then installed withinthe first member 105 at the time of the procedure. As discussedelsewhere herein, alternatively, the distraction mechanism can beintegral to the first member. Notably, the distraction mechanism 205 maybe configured to be utilized with other configurations or types ofimplants (not shown) other than the first member 105 of the depictedimplant device 104. Additionally or alternatively, the portions of thefirst member 105 which receive the distraction mechanism 205 can be madeof a standardized configuration, such that any given distractionmechanism can be fitted with any member 105 (such as, e.g., dependent ona specific treatment or specific spinal condition). Alternatively,heterogeneous sizes and/or overall expanded/fully contracted lengths ofdistraction may be provided. For instance, in one such approach, three(3) sizes are provided (e.g., small, medium, and large) for differentsized implant devices 104, such as for target intervertebral disc spaces(or patients) of different sizes. It is also appreciated that a singledistraction mechanism 205 can be substituted (with proper adaptation ofthe receiving host member 105) with two or more smaller mechanismsand/or the first member 105 may be configured to receive two or moredistraction mechanisms at various locations within the member, such asto permit finer adjustment of various particular portions (e.g.,anterior and/or posterior portions) of the implant relative to theinferior/superior surfaces of the vertebrae which it engages wheninstalled.

As can be seen in FIGS. 8A-8C, the expandable side 1058 (i.e., thenon-hinged side opposing the hinge 1052) of the first member 105 maycomprise two or more segments or pins 1056 or other such mechanisms,which may be configured to, inter alia, provide added rotationalstability to one or more of the implant sides. In some implementations,these pins or segments can also be configured to enable fastening orlocking of the upper and lower elements 1051 a, 1051 b relative to oneanother after the distraction mechanism(s) 205 has been inserted withinthe first member 105, and/or after the implant 104 has been insertedinto the target intervertebral space. For instance, the pins maycomprise threaded or rotation-lockable couplings which engage the upperand lower elements 1051 a, 1051 b so as to “clamp” the variable-heightimplant 104 and/or the distraction mechanism 205 in place once thedesired configuration (e.g., a desired height of the expandable side1058 of the first member 105) is achieved.

FIGS. 9A-9D illustrate multiple views of the exemplary embodiment of thedistraction mechanism 205. Many embodiments of expandable interbodyimplants are known in the art, and these devices employ a host ofdiffering mechanisms for device expansion and/or actuation. Thesemechanisms include, but are not limited to, mechanical linkages, wedges,pulleys, balloons, magnets, and/or pistons. It will be appreciated thatwhile a fluid-based piston assembly is shown as one option (e.g., usinga substantially incompressible working fluid), a compressible fluid(e.g., gas-based) working fluid may be used in certain alternateembodiments, as may a purely mechanical (i.e., non-fluidic) mechanism,such as a worm-screw drive, gear mechanism, or the like.

For example, in one embodiment, the distraction mechanism may comprise aworm screw drive or gear mechanism and an associated ridged track, whichis configured to be turned (wound) via an attachable and/or insertableadjustment tool. The tool may be operated in a first rotationaldirection to increase a height of the distraction mechanism 205, therebyincreasing a distance between upper and lower elements 1051 a, 1051 b.Further, in some examples, the tool may be operated in a secondrotational direction to decrease a height of the distraction mechanism205, thereby decreasing a distance between upper and lower elements 1051a, 1051 b. Various exemplary mechanical (non-fluidic) mechanisms thatcan be adapted into the distraction mechanism 205 for use in combinationwith the first member 105 are shown and described in U.S. Pat. No.7,909,870 and U.S. Patent Publication No. 2003/0163199, each of which isincorporated herein by reference in its entirety.

In another embodiment, the distraction mechanism may comprise a balloonmade of either non-compliant or compliant material which may be porousor non-porous, or may include a mesh material which may be coated orlined with a porous or non-porous material. The balloon may furtherinclude a port for coupling to a source of an inflation and/or expansionmedium (e.g., a gas, a liquid, a semi-solid, a gel, a liquid thathardens into a solid material, etc.) for inflating and/or expanding thedistraction mechanism. The devices may further include one or moreanchoring or attachment features for fixing the balloon within the firstmember 105. Actuation of such an embodiment of the distraction mechanismmay involve inflation of the balloon with the expansion medium, whereinthe act of balloon inflation provides at least part of the force neededto produce (i) the change in configuration of the structure of thehousing/structure distraction mechanism (such as an increase in theheight of the housing or a change in its dimension, such as lengthand/or width, of a segment of the housing, and/or (ii) the force neededto produce the change in configuration of the first member 105 (such asincrease in a distance between the upper and lower elements 1051 a, 1051b on at least one end (e.g., the expandable side 1058) of the firstmember 105). An exemplary balloon driven distraction mechanism that canbe adapted into the distraction mechanism 205 for use in combinationwith the first member 105 is shown and described in U.S. Patent No.8,123,807, which is incorporated herein by reference in its entirety.

While the distraction mechanism 205 is illustrated as a piston-baseddistraction mechanism, it is understood that any distraction mechanism(such as one or more of those described supra) may be alternativelyemployed.

Notably, the distraction mechanism 205 may also be configured forreversible mating with the first member 105 intra-operatively, whenhandled by the surgeon. That is, the distraction mechanism may have oneor more degrees of chirality or “handedness,” such that (i) it can beinserted in one orientation, and also in the opposite orientation (e.g.,rotated 180-degrees from the first orientation around an axis generallyparallel to the patient's spine), and/or (ii) can be inverted such thatits otherwise superior surface can function as its inferior surface, orvice versa). The foregoing approaches advantageously mitigate theimplanting surgeon “fumbling” with the mechanism 205 during surgery toachieve the proper orientation, and more importantly can avoid anyinstances where the mechanism 205 is installed in an improperorientation within the host member 105. To that end, the mechanism 205and its host member 105 may also include mechanical alignment featuressuch as keys, indexing, pins, etc. such that it can only be inserted oneway. Additionally or alternatively, the distraction mechanism may beintra-operatively removable from the first member 105, when handled bythe surgeon. That is, in an example where the pins 1056 provide clampingor locking of the first member 105 after distraction caused by thedistraction member 205, the distraction member may be reversiblydistracted (i.e., its height decreased) and removed from the firstmember prior to completion of the surgical procedure, while the firstmember retains its wedge-like configuration.

FIGS. 10A-10D illustrate exemplary configurations of the constituentmembers 2054 and 2058 of the distraction mechanism 205. In the exemplaryconfiguration, a piston 20546 is received within a cavity 20586 of themember 2058. Side protrusions 20548 are each received within cavities20588 and function to provide, inter alia, alignment and rotationalstability to the distraction mechanism 205. The member 2054 has surfaces20542 that abut the undersurface of the superior surface 1051 a of thefirst member 105, whereas surface 20544 extends through the window 1053(see FIGS. 6B and 11D). In certain embodiments, multiple sub-segments(such as sealants/gaskets, O-rings, etc.), which may be used with thedescribed piston-based approach, are known components of piston devices,and are not repeated here for diagrammatic simplicity. Note that in oneimplementation, the distraction mechanism 205 contains multipleapertures 20581 and 20583 that allow filling and/or bleeding of theworking fluid from the piston chamber. See also, e.g., U.S. PatentApplication Publication No. 2007/0093901, herein incorporated byreference in its entirety, which describes the exemplary use of pistonsin the manufacture of an expandable interbody implant, such as may alsobe used within the distraction mechanism 205 described above.

Advantageously, the exemplary embodiment of the distraction mechanism205 is configured such that it can be actuated from at least twoseparate sides. That is, the aperture(s) 20583 is/are formed within afirst surface and the aperture(s) 20581 is formed within a secondsurface of mechanism 205. Hence, different directions of approach can beused to actuate the distraction mechanism 205. In one implementation,the distraction mechanism 205 is configured to actuate whether theactuation tools approach (e.g., are attached to it) from either or bothof Direction F or Direction G of FIG. 7C; i.e., from one side of thedevice 104 or the other. For example, either or both of handles 10590illustrated in FIG. 7A can be used actuate the distraction mechanism205. The handles 10590 can also be provided regardless of the nature ofthe distraction mechanism used (mechanical linkages, wedges, pulleys,balloons, magnets, pistons and the like), such that the device may beactuated whether the first member 105 is approached from one side or theopposing second side. FIGS. 11B and 11D illustrate cross-sectional viewsof the exemplary embodiment of the distraction mechanism 205 alone (FIG.11A), and with the distraction mechanism 205 positioned within the firstmember 105 (FIG. 11C).

FIGS. 12A and 12B illustrate an example of a spinal deformity correctionthat may be achieved with use of one or more aspects of the disclosedinvention(s). In one implementation, a surgeon may be given a kitcomprising the first member 105, the distraction mechanism(s) 205, andhandling or installation instruments for, at least, positioning saidmembers, and/or actuation of the distraction mechanism(s) 205 (such ashandle(s) 10590). The patient can be prepared and a surgical procedureperformed by the surgeon as described above.

Exemplary Applications

In one embodiment, a variable-height implant may be configured to form alateral wedge configuration and be used to alter the spinal alignment ofa target functional spinal unit in the coronal plane in order to treatcoronal plane deformities such as, e.g., scoliosis. FIG. 12A shows alumbar spine with a coronal plane deformity (such as, for example,scoliosis). Application of the variable-height implant 104 (comprisingboth the first member 105 and the distraction mechanism 205) via one ormore of the surgical procedures described above produces the deformity(scoliosis) correction shown in FIG. 12B. Note that the implant 104advantageously may be implanted from either side of the spine (alongeither of directions “X” or “Y”; however, implantation of the depictedinferior (lower) implant, in the direction X, would be impossible underthe prior art. For example, an implant having a fixed wedge shape (i.e.,having a first side of a greater height than a second opposing side) isimplantable from only one side of the target intervertebral disc space.Specifically, the foregoing fixed wedge implant can only be insertedinto a disc space leading with the second opposing side (the side havinga smaller height) and trailing with the first side (having a greaterheight).

Returning to FIG. 12B, in one exemplary application of the presentinvention, the variable-height implant 104 is passed into the targetdisc space along direction X, while the implant is in the collapsedconfiguration 1040 (FIG. 7A) and the leading edge (the edge that entersthe disc space first) is of lesser or equal height to the trailing edgeof the implant (i.e., the edge that enters the disc space last). In analternate exemplary application, the variable-height implant 104 ispassed into the target disc space along direction Y, while the implantis in the collapsed configuration 1040 (FIG. 7A). In either application,the distraction mechanism 205 may be actuated after placement of the(assembled) implant 104 into the target disc space.

It will be appreciated, however, that in the alternate exemplaryapplication, the variable-height implant 104 may passed into the targetdisc space along direction Y, while the implant is in the expandedconfiguration 1042 (FIG. 7C) or a partially expanded configuration,after full or partial actuation of the distraction mechanism 205.

It will be further appreciated that the assembly of the implant device104 may be conducted after the first member 105 is inserted into thetarget disc space in some cases. Specifically, in one variant, the firstmember 105 alone is inserted in the direction X into the target space,and then subsequently, the surgeon accesses the disc space (and implanthost member 105) via a different approach. In another variant, the firstmember 105 alone is inserted via an anterior approach (having a largersurgical corridor) into the target disc space, and then subsequently,the surgeon accesses the disc space (and the first member 105) via aposterior approach (having a smaller surgical corridor). In each of theforegoing variants, the distraction mechanism 250 is initially in itscompletely compressed state (i.e., smallest possible vertical profile,such that the surgeon can slide the mechanism 250 into e.g., a lateralgroove formed on the first member 105 (not shown), or even separate theupper and lower elements 1051 a, 1051 b far enough while in the discspace such that the distraction mechanism can be inserted therebetween(and subsequently expanded as described supra).

As previously discussed, a variable-height implant may be configured toform an anterior to posterior wedge configuration and be used to treatsagittal plane deformity such as, e.g., abnormal lordosis and/orkyphosis—as shown in the implant 104 a of FIGS. 13A and 13B. This deviceembodiment may be used to correct sagittal plane deformity, and would beemployed to perform the “second method embodiment” discussed above. (Itis understood that whether used to correct coronal or sagittal planedeformity, the implant may be delivered into the disc space using anyknown surgical approach for device implantation. Specifically,approaches 505, 507 and/or 507 of FIG. 5, may be employed).

FIG. 13A illustrates the implant 104 a when viewed from above (forexample, after implantation) including a distraction mechanism 205 apositioned in the anterior aspect of a first member 105 a (includingthree pins 1056 a). FIG. 13B shows a side view —as would be seen withthe device of FIG. 13A is viewed along direction A. It will beappreciated that the implant 104 a may be used with any of the surgicalprocedures and may include the variations discussed herein. It will befurther appreciated that the variable height implant 104 a (in use) canbe included in a kit with and/or used in combination with the implant104 during a surgical procedure.

In yet another embodiment, a variable-height implant may be configuredto form a wedge configuration used to treat translational deformitiessuch as e.g., anterior/posterior or lateral spondylolisthesis.

It will be appreciated that the flexibility in use and configuration, aswell as the modularity, of the first members 105, 105 a and thedistraction mechanisms 205, 205 a are advantageous over priorimplantation devices and methods. In other words, the configuration ofthe implant assembly and the method of implantation can be adapted by asurgeon to be spinal condition and/or patient specific. Such specificitymay enable a surgeon to map out and prepare the implant components andsurgical strategy prior to the implantation procedure. Alternatively,the surgeon can respond “on the fly” as a surgery progresses, ifnecessary, to provide a “best fit” implant configuration andimplantation process (particularly in response to unforeseen issues thatmay unexpectedly arise and/or in treatment of especially complex spinalconditions). For example, any of the first members 105, 105 a or thedistraction mechanisms 205, 205 a can be utilized as a free standingimplant (e.g., where the distraction mechanism is implanted in thetarget disc space and actuated without prior insertion into the first(host) member, where the first member is inserted without a distractionmechanism and does not require distraction after implantation, where thefirst member is implanted with and distracted by the distractionmechanism, which is subsequently removed from the first member, etc.),and/or they can be used in combination (e.g., where the distractionmechanism is fitted within and is actuatable within the first member, asdescribed supra). In other examples, various implant assemblies can beused in combination within the same target FSU or other target FSUs(e.g., adjacent FSUs) to treat complex spinal curvature conditions. Thevarious implant assemblies can be inserted from any desired approachand/or entry point of the target FSU (such as those discussed supra).

Methods

One embodiment of a method of use for the implant assemblies disclosedherein includes inserting an implant assembly into the targetintervertebral disc space using any desired surgical approach to thespine (such as those described supra). The assembly comprises a first(host) member and a second member comprising a distraction mechanism.The first member comprises at least a first and a second segment thatare configured to move relative to one another, wherein, for example,movement of the first segment relative to the second segment apartincreases a height, a length, and/or a width of the first member.Preferably, but not necessarily, the first member does not comprise itsown distraction mechanism; however in some examples, the first membermay comprise an integral distraction mechanism. In one variant, themethod further includes anchoring one of upper and lower elements of thefirst member to one of the superior and inferior vertebral bones of thetarget FSU (such as, for example, by via a first bone screw). Further,the method may include anchoring the other of the upper and lowerelements of the first member to the other of the superior and inferiorvertebral bones of the target FSU (such as, for example, by via a secondbone screw).

The method further includes actuating the distraction mechanism afterpositioning of the implant assembly at the desired location within thetarget disc space. The first member and the second member are coupledsuch the act of actuating of the distraction mechanism (the secondmember) causes a distance between the upper and lower elements toincrease on at least one end or side of the first member. Additionally,a distance between one or more portions of the upper and lower elementsmay decrease, and/or both ends a distance between the upper and lowerelements at both ends of the first member may increase. For example, theupper and lower elements the first member to move away from (or towards)one another. In another example, one of the upper and lower elements maymove away from (or towards) the other of the upper and lower elements.In this way, the act of actuating of the distraction mechanism of thesecond member increases at least one of the height, length, and/or widthdimensions of the implant assembly and alters the distance between thesuperior and inferior bones within at least one plane (coronal, axial,and/or sagittal planes) of the spine.

Alternate Configurations

It is appreciated that while the foregoing description describes animplant device 104 that may have one side (but not the other) increasedin height, the present disclosure contemplates alternate implantconfigurations which have more degrees of freedom. For instance, in onesuch configuration, both sides of the implant can be adjusted as toheight, whether increased or decreased, so as to obtain an optimalrelative height/size profile for the target space. In one suchimplementation (not shown), rather than being hinged as shown in FIGS.6A and 6B, the pivot or axes of rotation of the implant upper and lowersegments is disposed more centrally to the implant 104, such that thetwo sides of the implant can “toggle” or alternate.

In yet another implementation, both sides of the implant can increase ordecrease in tandem with one another, such as via use of a hinge or pivotthat is centrally located on the implant, yet which can also translatein a direction normal to the plane of the implant device (i.e., suchthat the upper and lower elements 1051 a, 1051 b can move closer orfurther apart from one another, while also having different heights ifdesired.

In such configurations, more than one distraction member 205 may also beutilized, such as where one distraction member is disposed at or neareach end (side) of the implant device.

Once the desired configuration is achieved, the translation mechanism(e.g., a set screw or other mechanism) can be fastened and locked so asto make the configuration effectively permanent (at least during thelifetime of the implantation). Adhesives or yet other means formaintaining the desired position can be utilized as well. In onevariant, the distraction mechanism can be removed after fastening orlocking of the first member of the desired position.

In another embodiment for the variable height implant, the implantabledevice comprises at least two members, the first being a body (which maycomprise more than one segment) configured to abut each of the superiorand inferior vertebral bones of the target FSU containing the targetintervertebral disc space. In one implementation, the first member iscomprised of a solid material, which may further be malleable so as tofacilitate conformance with at least portions of the target space, andis adapted for implantation into the subject. In another implementation,the first member may be at least partially comprised of a balloon orvariable-geometry inflatable bladder. The second member comprises adistraction mechanism that provides the force needed to increase theheight of one or both lateral sides of the implant, as well as thestructure to maintain the increased height of the implant. In onevariant, the distraction mechanism comprises a separate member that canbe reversibly inserted/coupled onto the first member by the operator atthe time of the surgical procedure.

In another variant, the second member is permanently attached to orintegrally formed with the first member. In one implementation, themechanism comprises an actuatable mechanical device, such as a hydraulicpiston. In another implementation, the mechanism is at least partiallycomprised of a balloon.

In still another embodiment, the implant device is a kit comprised of atleast the first and second members. In one implementation, the first andsecond members can be used alone or in combination depending on thespecific condition or configuration of a spine of a patient.

The disclosed device embodiments or any of their components can be madeof any biologically adaptable or compatible materials. Materialsconsidered acceptable for biological implantation are well known andinclude, but are not limited to, stainless steel, titanium, tantalum,combination metallic alloys, various plastics (such as PEEK and thelike), resins, ceramics, biologically absorbable materials and the like.

Any components may be also coated/made with osteo-conductive (such asdeminerized bone matrix, hydroxyapatite, and the like) and/orosteo-inductive (such as Transforming Growth Factor “TGF-B,”Platelet-Derived Growth Factor “PDGF,” Bone-Morphogenic Protein “BMP,”and the like) bio-active materials that promote bone formation.

Further, any surface may be made with a porous ingrowth surface (suchas, for example, porous titanium, titanium wire mesh, plasma-sprayedtitanium, tantalum, porous CoCr, and the like), provided with abioactive coating, made using tantalum, and/or helical rosette carbonnanotubes (or other carbon nanotube-based coating) in order to promotebone in-growth or establish a mineralized connection between the boneand the implant, and reduce the likelihood of implant loosening. Thesystem or any of its components may be made by “additive manufacturing”,such as, for example, “3D” printing.

Lastly, the system or any of its components can also be entirely orpartially made of a shape memory material or other deformable material.

While this specification contains certain specific features andattributes, these should not be construed as limitations on the scope ofwhat is claimed or of what may be claimed, but rather as descriptions offeatures specific to particular embodiments. Certain features that aredescribed in this specification in the context of separate embodimentscan also be implemented in combination in a single embodiment.Conversely, various features that are described in the context of asingle embodiment can also be implemented in multiple embodimentsseparately or in any suitable sub-combination. Moreover, althoughfeatures may be described above as acting in certain combinations andeven initially claimed as such, one or more features from a claimedcombination can in some cases be excised from the combination, and theclaimed combination may be directed to a sub-combination or a variationof a sub-combination. Similarly, while operations are depicted in thedrawings in a particular order, this should not be understood asrequiring that such operations be performed in the particular ordershown or in sequential order, or that all illustrated operations beperformed, to achieve desirable results. Only a few examples andimplementations are disclosed. Variations, modifications andenhancements to the described examples and implementations and otherimplementations may be made based on what is disclosed.

It will also be recognized that while certain aspects of the disclosureare described in terms of a specific sequence of steps of a method,these descriptions are only illustrative of the broader methods of thedisclosure, and may be modified as required by the particularapplication. Certain steps may be rendered unnecessary or optional undercertain circumstances. Additionally, certain steps or functionality maybe added to the disclosed embodiments, or the order of performance oftwo or more steps permuted. All such variations are considered to beencompassed within the disclosure disclosed and claimed herein.

What is claimed is:
 1. An implantable device configured for implantationwithin an intervertebral disc space, the intervertebral disc spacedisposed between a superior vertebral bone and an inferior vertebralbone, the implantable device comprising: a first member, the firstmember comprising: a first top surface configured to at least partiallyabut the superior vertebral bone; a first bottom surface movably coupledto the first top surface, the first bottom surface configured to atleast partially abut the inferior vertebral bone; a first side surface;a second side surface opposing the first side surface; a receivingsegment configured to reversibly couple with at least a segment of asecond member, the second member comprising at least a second topsurface, a second bottom surface, and an intervening distractionmechanism at least partially disposed between the second top surface andthe second bottom surface, the at least segment of the second membercomprising at least a segment of one of the second top surface or thesecond bottom surface, the distraction mechanism of the second memberconfigured to be selectively actuatable to increase of a first distancebetween the second top surface and the second bottom surface of thesecond member, and thereby cause increase of a second distance betweenat least a portion of the first top surface and the first bottomsurface; and a selectively actuatable locking mechanism, the selectivelyactuatable locking mechanism (i) being a separate structure relative tothe second member, and (ii) being configured to immobilize the first topsurface relative to the first bottom surface after actuation of thedistraction mechanism; wherein the receiving segment of the first memberis further configured to, after actuation of the locking mechanism andimmobilization of the first top surface relative to the first bottomsurface, (i) uncouple from the at least segment of one of the second topsurface or the second bottom surface, and (ii) enable removal of thesecond top surface and the second bottom surface of the second memberfrom the first member while the first top surface remains immobilizedrelative to the first bottom surface.
 2. The implantable device of claim1, wherein the first member further comprises a hinge segment disposedat the second side surface; and wherein the actuation of the distractionmechanism of the second member is further configured to cause at leastpartial rotation of the first top surface relative to the first bottomsurface around an axis of the hinge segment.
 3. The implantable deviceof claim 1, wherein the receiving segment at least in part comprises anaperture in at least one of the first top surface and the first bottomsurface of the first member, the aperture configured to receive the atleast segment of one of the second top surface or the second bottomsurface of the second member, the received at least segment of the oneof the second top surface or the second bottom surface of the secondmember configured to (i) extend through the aperture, and (ii) abut asegment of one of the superior vertebral bone or the inferior vertebralbone.
 4. The implantable device of claim 1, wherein the receivingsegment is configured to receive the second member at least partiallywithin the first member, such that the second member is disposed atleast partially between the first top surface and the first bottomsurface.
 5. The implantable device of claim 1, wherein the first topsurface of the first member is configured to rotate relative to thefirst bottom surface, the first member configured to assume awedge-shaped configuration after the actuation of the distractionmechanism of the second member.
 6. A device assembly configured for atleast a portion thereof to be at least partially within anintervertebral disc space of a spinal column, the device assemblycomprising: a first member comprising: a first top element; a firstbottom element movably coupled to the first top element; and a firstdistraction mechanism that is configured to be actuated; and a secondmember, the second member configured to (i) at least partially receivethe first member, and (ii) be separable from the first member, thesecond member comprising: a second top element; a second bottom elementmovably coupled to the second top element; a coupling that is configuredto reversibly couple with the first member; wherein the first member isconfigured such that, when the coupling of the second member isuncoupled from the first member, actuation of the first distractionmechanism is configured to cause an increase of a first distance betweenat least a portion of the first top element and the first bottom elementof the first member; wherein the first member and the second member areconfigured such that, when the first member is coupled to the couplingof the second member, the actuation of the first distraction mechanismis configured to cause increase in a second distance between at least aportion of the second top element and the second bottom element of thesecond member; and wherein at least a segment of one of the first topelement or the first bottom element comprises a surface having one ormore projections configured to abut and fixate onto a segment of avertebral bone adjacent to the intervertebral disc space.
 7. The deviceassembly of claim 6, wherein the coupling is at least partially disposedbetween the second top element and the second bottom element of thesecond member.
 8. The device assembly of claim 6, wherein at least oneof the second top element and the second bottom element of the secondmember comprises an aperture configured to receive the at least segmentof one of the first top element or the first bottom element of the firstmember, the at least segment of one of the first top element or thefirst bottom element configured to extend through the aperture in orderto abut the segment of the vertebral bone.
 9. The device assembly ofclaim 6, wherein the second member further comprises a multi-positionlocking mechanism configured to immobilize the second top elementrelative to the second bottom element of the second member, themulti-position locking mechanism being a separate structure relative tothe first member.
 10. The device assembly of claim 9, wherein: the firstmember is configured to reversibly uncouple from the coupling of thesecond member after (i) locking of the multi-position locking mechanismof the second member, and (ii) immobilization of the second top elementrelative to the second bottom element; the first member is sized forremoval from the intervertebral disc space after uncoupling from thecoupling of the second member; and the first bottom element of the firstmember comprises a rigid first bottom surface.
 11. The device assemblyof claim 6, wherein the second top element of the second member isconfigured to rotate relative to the second bottom element of the secondmember, the second member further configured to have a wedge-shapedconfiguration after actuation of the distraction mechanism of the firstmember when the first member is coupled to the coupling of the secondmember.
 12. A kit for treatment of a spinal segment, the spinal segmentcomprising at least a superior vertebral bone, an inferior vertebralbone, and an intervertebral disc space disposed between the superiorvertebral bone and the inferior vertebral bone, the kit comprising: adistraction module, the distraction module comprising a first top side,a first bottom side opposing the first top side and movably coupled tothe first top side, and a distraction mechanism, the distractionmechanism configured to (i) distract the first top side away from thefirst bottom side, and (ii) retain the first top side and the firstbottom side in a distracted configuration; at least one housing module,the at least one housing module configured for at least partialimplantation into the intervertebral disc space, the at least onehousing module comprising a second top side, a second bottom sideopposing the second top side and movably coupled to the second top side,and a coupler, the coupler configured to reversibly couple with at leasta segment of the distraction module; and a non-implantable driver, thenon-implantable driver configured to (i) at least partially couple withthe distraction module, and (ii) actuate the distraction mechanism;wherein the distraction module, when the at least segment of thedistraction module is coupled to the coupler of the at least one housingmodule, is configured to form an assembly with the at least one housingmodule; wherein the non-implantable driver is configured to actuate thedistraction module in the assembly to produce concurrent (i) distractionof the first top side away from the first bottom side, and (ii)distraction of the second top side away from the second bottom side; andwherein the at least one housing module is configured such that thenon-implantable driver is incapable of producing distraction of thesecond top side away from the second bottom side when the at leastsegment of the distraction module is uncoupled from the at least onehousing module.
 13. The kit of claim 12, wherein the distraction modulecomprises unitary device.
 14. The kit of claim 12, wherein the at leastone housing module comprises two or more housing modules, the two ormore housing modules each configured to differ from another of the twoor more housing modules in at least one dimension thereof.
 15. The kitof claim 14, wherein the at least segment of the distraction module isconfigured to be received in each of the two more housing modules. 16.The kit of claim 12, wherein the at least one housing module isconfigured to receive at least one other distraction module.
 17. The kitof claim 12, wherein the at least one housing module further comprises alocking feature, the locking feature comprising a separate structurefrom the distraction mechanism.
 18. The kit of claim 17, wherein: the atleast segment of the distraction module is configured to be uncoupledfrom coupler of the at least one housing module after distraction of thesecond top side away from the second bottom side into a distractedposition; and the locking feature is configured to retain the second topside and the second bottom side in the distracted position after the atleast segment of the distraction module is uncoupled from the coupler ofthe at least one housing module.
 19. The kit of claim 18, wherein thecoupler of the at least one housing module is configured for removal ofthe at least segment of the distraction module after positing theassembly within the intervertebral disc space.
 20. The kit of claim 12,wherein the at least one housing module is devoid of a distractionmechanism that is independent of the distraction module.
 21. The kit ofclaim 12, further comprising one or more other non-implantable drivers.22. The kit of claim 12, further comprising one or more otherdistraction modules.
 23. The kit of claim 22, wherein the distractionmodule comprises a first distraction module and the one or more otherdistraction modules comprise at least a second distraction module, thefirst distraction module configured to produce a first maximumdistraction distance between the first top side and the first bottomside, the second distraction module configured to produce a secondmaximum distraction distance between the first top side and the firstbottom side, the first maximum distraction distance being greater thanthe second maximum distraction distance.
 24. The kit of claim 12,wherein: the at least one housing module further comprises a front sideand a back side opposing the front side; and the at least one housingmodule is configured such that actuation of the distraction moduleproduces a greater change in a height of the front side than in a heightof the back side.
 25. A kit for treatment of a spinal segment, thespinal segment comprising at least a superior vertebral bone, aninferior vertebral bone and an intervertebral disc space disposedbetween the superior vertebral bone and the inferior vertebral bone, thekit comprising: a distraction module comprising a first top side, afirst bottom side opposing the first top side and movable relative tothe first top side, a distraction mechanism, an actuation memberconfigured to actuate the distraction mechanism, the distractionmechanism, upon the actuation thereof, configured to: (i) distract thefirst top side away from the first bottom side, and (ii) retain thefirst top side and the first bottom side in a distracted configuration;at least one housing module comprising a second top side, a secondbottom side opposing the second top side and movable relative to thesecond top side, and a coupler configured to reversibly seat at least asegment of the distraction module, the at least one housing moduleconfigured for at least partial implantation into the intervertebraldisc space; and a non-implantable driver configured to couple with theactuation member of the distraction module in order to cause theactuation member to actuate the distraction mechanism; wherein, when theat least segment of the distraction module is seated in the coupler ofthe at least one housing module, the distraction mechanism, upon theactuation thereof, is further configured to cause the distraction of thefirst top side away from the first bottom side as well as concurrentdistraction of the second top side away from the second bottom side; andwherein the distraction module and the at least one housing module areconfigured to form an assembly when the at least one segment of thedistraction module is seated in the coupler of the at least one housingmodule.
 26. The kit of claim 25, wherein the non-implantable driver andthe at least one housing module are configured such that thenon-implantable driver is incapable of causing distraction of the secondtop side away from the opposing second bottom side when the at least onesegment of the distraction module is unseated from the coupler of the atleast one housing module.
 27. The kit of claim 25, wherein the at leastone housing module further comprises a locking feature, the lockingfeature comprising a separate structure from the distraction module. 28.The kit of claim 27, wherein: the at least segment of the distractionmodule is configured to be uncoupled from coupler of the at least onehousing module after distraction of the second top side away from thesecond bottom side into a distracted position; and the locking featureis configured to retain the second top side and the second bottom sidein the distracted position after the at least segment of the distractionmodule is uncoupled from the coupler of the at least one housing module.29. The kit of claim 25, wherein the at least one housing module isdevoid of an additional distraction mechanism that is independent of thedistraction module.